Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753753Ab3EMRrO (ORCPT ); Mon, 13 May 2013 13:47:14 -0400 Received: from mail-pd0-f178.google.com ([209.85.192.178]:50640 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753316Ab3EMRrJ (ORCPT ); Mon, 13 May 2013 13:47:09 -0400 From: Soren Brinkmann To: Michal Simek , Josh Cartwright , Mike Turquette , Lars-Peter Clausen , Peter Crosthwaite Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Arnd Bergmann , Russell King , Stephen Warren , Soren Brinkmann Subject: [PATCH v2 2/5] clk: zynq: Factor out PLL driver Date: Mon, 13 May 2013 10:46:36 -0700 Message-Id: <1368467199-8702-3-git-send-email-soren.brinkmann@xilinx.com> X-Mailer: git-send-email 1.8.2.3 In-Reply-To: <1368467199-8702-1-git-send-email-soren.brinkmann@xilinx.com> References: <1368467199-8702-1-git-send-email-soren.brinkmann@xilinx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6719 Lines: 257 Refactor the PLL driver so it works with the clock controller driver. Signed-off-by: Soren Brinkmann --- drivers/clk/zynq/pll.c | 235 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 235 insertions(+) create mode 100644 drivers/clk/zynq/pll.c diff --git a/drivers/clk/zynq/pll.c b/drivers/clk/zynq/pll.c new file mode 100644 index 0000000..47e307c --- /dev/null +++ b/drivers/clk/zynq/pll.c @@ -0,0 +1,235 @@ +/* + * Zynq PLL driver + * + * Copyright (C) 2013 Xilinx + * + * Sören Brinkmann + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License v2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ +#include +#include +#include +#include + +/** + * struct zynq_pll + * @hw: Handle between common and hardware-specific interfaces + * @pll_ctrl: PLL control register + * @pll_status: PLL status register + * @lock: Register lock + * @lockbit: Indicates the associated PLL_LOCKED bit in the PLL status + * register. + */ +struct zynq_pll { + struct clk_hw hw; + void __iomem *pll_ctrl; + void __iomem *pll_status; + spinlock_t *lock; + u8 lockbit; +}; +#define to_zynq_pll(_hw) container_of(_hw, struct zynq_pll, hw) + +/* Register bitfield defines */ +#define PLLCTRL_FBDIV_MASK 0x7f000 +#define PLLCTRL_FBDIV_SHIFT 12 +#define PLLCTRL_BPQUAL_MASK (1 << 3) +#define PLLCTRL_PWRDWN_MASK 2 +#define PLLCTRL_PWRDWN_SHIFT 1 +#define PLLCTRL_RESET_MASK 1 +#define PLLCTRL_RESET_SHIFT 0 + +/** + * zynq_pll_round_rate() - Round a clock frequency + * @hw: Handle between common and hardware-specific interfaces + * @rate: Desired clock frequency + * @prate: Clock frequency of parent clock + * Returns frequency closest to @rate the hardware can generate. + */ +static long zynq_pll_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + u32 fbdiv; + + fbdiv = DIV_ROUND_CLOSEST(rate, *prate); + if (fbdiv < 13) + fbdiv = 13; + else if (fbdiv > 66) + fbdiv = 66; + + return *prate * fbdiv; +} + +/** + * zynq_pll_recalc_rate() - Recalculate clock frequency + * @hw: Handle between common and hardware-specific interfaces + * @parent_rate: Clock frequency of parent clock + * Returns current clock frequency. + */ +static unsigned long zynq_pll_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct zynq_pll *clk = to_zynq_pll(hw); + u32 fbdiv; + + /* + * makes probably sense to redundantly save fbdiv in the struct + * zynq_pll to save the IO access. + */ + fbdiv = (readl(clk->pll_ctrl) & PLLCTRL_FBDIV_MASK) >> + PLLCTRL_FBDIV_SHIFT; + + return parent_rate * fbdiv; +} + +/** + * zynq_pll_is_enabled - Check if a clock is enabled + * @hw: Handle between common and hardware-specific interfaces + * Returns 1 if the clock is enabled, 0 otherwise. + * + * Not sure this is a good idea, but since disabled means bypassed for + * this clock implementation we say we are always enabled. + */ +static int zynq_pll_is_enabled(struct clk_hw *hw) +{ + unsigned long flags = 0; + u32 reg; + struct zynq_pll *clk = to_zynq_pll(hw); + + spin_lock_irqsave(clk->lock, flags); + + reg = readl(clk->pll_ctrl); + + spin_unlock_irqrestore(clk->lock, flags); + + return !(reg & (PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK)); +} + +/** + * zynq_pll_enable - Enable clock + * @hw: Handle between common and hardware-specific interfaces + * Returns 0 on success + */ +static int zynq_pll_enable(struct clk_hw *hw) +{ + unsigned long flags = 0; + u32 reg; + struct zynq_pll *clk = to_zynq_pll(hw); + + if (zynq_pll_is_enabled(hw)) + return 0; + + pr_info("PLL: enable\n"); + + /* Power up PLL and wait for lock */ + spin_lock_irqsave(clk->lock, flags); + + reg = readl(clk->pll_ctrl); + reg &= ~(PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK); + writel(reg, clk->pll_ctrl); + while (!(readl(clk->pll_status) & (1 << clk->lockbit))) + ; + + spin_unlock_irqrestore(clk->lock, flags); + + return 0; +} + +/** + * zynq_pll_disable - Disable clock + * @hw: Handle between common and hardware-specific interfaces + * Returns 0 on success + */ +static void zynq_pll_disable(struct clk_hw *hw) +{ + unsigned long flags = 0; + u32 reg; + struct zynq_pll *clk = to_zynq_pll(hw); + + if (!zynq_pll_is_enabled(hw)) + return; + + pr_info("PLL: shutdown\n"); + + /* shut down PLL */ + spin_lock_irqsave(clk->lock, flags); + + reg = readl(clk->pll_ctrl); + reg |= PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK; + writel(reg, clk->pll_ctrl); + + spin_unlock_irqrestore(clk->lock, flags); +} + +static const struct clk_ops zynq_pll_ops = { + .enable = zynq_pll_enable, + .disable = zynq_pll_disable, + .is_enabled = zynq_pll_is_enabled, + .round_rate = zynq_pll_round_rate, + .recalc_rate = zynq_pll_recalc_rate +}; + +/** + * clk_register_zynq_pll() - Register PLL with the clock framework + * @np Pointer to the DT device node + */ +struct clk *clk_register_zynq_pll(const char *name, const char *parent, + void __iomem *pll_ctrl, void __iomem *pll_status, u8 lock_index, + spinlock_t *lock) +{ + struct zynq_pll *pll; + struct clk *clk; + u32 reg; + const char *parent_arr[1] = {parent}; + unsigned long flags = 0; + struct clk_init_data initd = { + .name = name, + .parent_names = parent_arr, + .ops = &zynq_pll_ops, + .num_parents = 1, + .flags = 0 + }; + + pll = kmalloc(sizeof(*pll), GFP_KERNEL); + if (!pll) { + pr_err("%s: Could not allocate Zynq PLL clk.\n", __func__); + return ERR_PTR(-ENOMEM); + } + + /* Populate the struct */ + pll->hw.init = &initd; + pll->pll_ctrl = pll_ctrl; + pll->pll_status = pll_status; + pll->lockbit = lock_index; + pll->lock = lock; + + spin_lock_irqsave(pll->lock, flags); + + reg = readl(pll->pll_ctrl); + reg &= ~PLLCTRL_BPQUAL_MASK; + writel(reg, pll->pll_ctrl); + + spin_unlock_irqrestore(pll->lock, flags); + + clk = clk_register(NULL, &pll->hw); + if (WARN_ON(IS_ERR(clk))) + goto free_pll; + + return clk; + +free_pll: + kfree(pll); + + return clk; +} -- 1.8.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/